Electrochemical Fabrication Process Including Process Monitoring, Making Corrective Action Decisions, and Taking Appropriate Actions

ABSTRACT

Electrochemical fabrication processes and apparatus for producing multi-layer structures include operations or means for providing enhanced monitoring of build operations or detection of the results of build operations, operations or means for build problem recognition, operations or means for evaluation of corrective action options, operations or means for making corrective action decisions, and operations or means for executing actions based on those decisions.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.10/995,609 (Microfabrica Docket No. P-US124-A-MF), filed Nov. 22, 2004which in turn claims benefit of U.S. Provisional Patent Application No.60/523,951 (Docket No. P-US069-A-MF), filed Nov. 20, 2003, and is acontinuation-in-part of U.S. patent application Ser. Nos. 10/434,494(Docket No. P-US057-A-SC), and 10/434,519 (Docket No. P-US068-A-MG),both filed on May 7, 2003. Application Ser. No. 10/434,494 claimsbenefit of U.S. Provisional Patent Application No. 60/379,132 (DocketNo. P-US007-A-SC), filed on May 8, 2002 and application Ser. No.10/434,519 claims benefit of U.S. Provisional Patent Application No.60/379,130 (Docket No. P-US028-A-MG), filed on May 8, 2002. All of theseapplications are incorporated herein in their entireties as if set forthin full.

FIELD OF THE INVENTION

Embodiments of this invention relate to the field of electrochemicalfabrication and the associated formation of multi-layerthree-dimensional structures and more specifically to processes that aremonitored, failures detected, and corrective actions taken. Some buildprocesses may involve the monitoring, build problem recognition,evaluation of corrective action options, making corrective actiondecisions, and executing actions based on those decisions.

BACKGROUND

A technique for forming three-dimensional structures (e.g. parts,components, devices, and the like) from a plurality of adhered layerswas invented by Adam L. Cohen and is known as ElectrochemicalFabrication. It is being commercially pursued by Microfabrica® Inc. ofVan Nuys, Calif. under the name EFAB®. This technique was described inU.S. Pat. No. 6,027,630, issued on Feb. 22, 2000 to Adam Cohen. Someembodiments of this electrochemical fabrication technique allow theselective deposition of a material using a mask that includes patternedconformable material on a support structure that is independent of thesubstrate onto which plating will occur. When desiring to perform anelectrodeposition using the mask, the conformable portion of the mask isbrought into contact with a substrate while in the presence of a platingsolution such that the contact of the conformable portion of the mask tothe substrate inhibits deposition at selected locations. Forconvenience, these masks might be generically called conformable contactmasks; the masking technique may be generically called a conformablecontact mask plating process. More specifically, in the terminology ofMicrofabrica Inc. such masks have come to be known as INSTANT MASKS™ andthe process known as INSTANT MASKING™ or INSTANT MASK™ plating.Selective depositions using conformable contact mask plating may be usedto form single layers of material or may be used in a process to formmulti-layer structures. The teachings of the '630 patent are herebyincorporated herein by reference as if set forth in full herein. Sincethe filing of the patent application that led to the above noted patent,various papers about conformable contact mask plating (i.e. INSTANTMASKING) and electrochemical fabrication have been published:

-   1. A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P. Will,    “EFAB: Batch production of functional, fully-dense metal parts with    micro-scale features”, Proc. 9th Solid Freeform Fabrication, The    University of Texas at Austin, p 161, August 1998.-   2. A. Cohen, G. Zhang, F. Tseng, F. Mansfeld, U. Frodis and P. Will,    “EFAB: Rapid, Low-Cost Desktop Micromachining of High Aspect Ratio    True 3-D MEMS”, Proc. 12th IEEE Micro Electro Mechanical Systems    Workshop, IEEE, p 244, January 1999.-   3. A. Cohen, “3-D Micromachining by Electrochemical Fabrication”,    Micromachine Devices, March 1999.-   4. G. Zhang, A. Cohen, U. Frodis, F. Tseng, F. Mansfeld, and P.    Will, “EFAB: Rapid Desktop Manufacturing of True 3-D    Microstructures”, Proc. 2nd International Conference on Integrated    MicroNanotechnology for Space Applications, The Aerospace Co., April    1999.-   5. F. Tseng, U. Frodis, G. Zhang, A. Cohen, F. Mansfeld, and P.    Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures    using a Low-Cost Automated Batch Process”, 3rd International    Workshop on High Aspect Ratio MicroStructure Technology (HARMST'99),    June 1999.-   6. A. Cohen, U. Frodis, F. Tseng, G. Zhang, F. Mansfeld, and P.    Will, “EFAB: Low-Cost, Automated Electrochemical Batch Fabrication    of Arbitrary 3-D Microstructures”, Micromachining and    Microfabrication Process Technology, SPIE 1999 Symposium on    Micromachining and Microfabrication, September 1999.-   7. F. Tseng, G. Zhang, U. Frodis, A. Cohen, F. Mansfeld, and P.    Will, “EFAB: High Aspect Ratio, Arbitrary 3-D Metal Microstructures    using a Low-Cost Automated Batch Process”, MEMS Symposium, ASME 1999    International Mechanical Engineering Congress and Exposition,    November, 1999.-   8. A. Cohen, “Electrochemical Fabrication (EFAB™)”, Chapter 19 of    The MEMS Handbook, edited by Mohamed Gad-El-Hak, CRC Press, 2002.-   9. “Microfabrication—Rapid Prototyping's Killer Application”, pages    1-5 of the Rapid Prototyping Report, CAD/CAM Publishing, Inc., June    1999.

The disclosures of these nine publications are hereby incorporatedherein by reference as if set forth in full herein.

The electrochemical deposition process may be carried out in a number ofdifferent ways as set forth in the above patent and publications. In oneform, this process involves the execution of three separate operationsduring the formation of each layer of the structure that is to beformed:

(1) Selectively depositing at least one material by electrodepositionupon one or more desired regions of a substrate.

(2) Then, blanket depositing at least one additional material byelectrodeposition so that the additional deposit covers both the regionsthat were previously selectively deposited onto, and the regions of thesubstrate that did not receive any previously applied selectivedepositions.

(3) Finally, planarizing the materials deposited during the first andsecond operations to produce a smoothed surface of a first layer ofdesired thickness having at least one region containing the at least onematerial and at least one region containing at least the one additionalmaterial.

After formation of the first layer, one or more additional layers may beformed adjacent to the immediately preceding layer and adhered to thesmoothed surface of that preceding layer. These additional layers areformed by repeating the first through third operations one or more timeswherein the formation of each subsequent layer treats the previouslyformed layers and the initial substrate as a new and thickeningsubstrate.

Once the formation of all layers has been completed, at least a portionof at least one of the materials deposited is generally removed by anetching process to expose or release the three-dimensional structurethat was intended to be formed.

The preferred method of performing the selective electrodepositioninvolved in the first operation is by conformable contact mask plating.In this type of plating, one or more conformable contact (CC) masks arefirst formed. The CC masks include a support structure onto which apatterned conformable dielectric material is adhered or formed. Theconformable material for each mask is shaped in accordance with aparticular cross-section of material to be plated. At least one CC maskis needed for each unique cross-sectional pattern that is to be plated.

The support for a CC mask is typically a plate-like structure formed ofa metal that is to be selectively electroplated and from which materialto be plated will be dissolved. In this typical approach, the supportwill act as an anode in an electroplating process. In an alternativeapproach, the support may instead be a porous or otherwise perforatedmaterial through which deposition material will pass during anelectroplating operation on its way from a distal anode to a depositionsurface. In either approach, it is possible for CC masks to share acommon support, i.e. the patterns of conformable dielectric material forplating multiple layers of material may be located in different areas ofa single support structure. When a single support structure containsmultiple plating patterns, the entire structure is referred to as the CCmask while the individual plating masks may be referred to as“submasks”. In the present application such a distinction will be madeonly when relevant to a specific point being made.

In preparation for performing the selective deposition of the firstoperation, the conformable portion of the CC mask is placed inregistration with and pressed against a selected portion of thesubstrate (or onto a previously formed layer or onto a previouslydeposited portion of a layer) on which deposition is to occur. Thepressing together of the CC mask and substrate occur in such a way thatall openings, in the conformable portions of the CC mask contain platingsolution. The conformable material of the CC mask that contacts thesubstrate acts as a barrier to electrodeposition while the openings inthe CC mask that are filled with electroplating solution act as pathwaysfor transferring material from an anode (e.g. the CC mask support) tothe non-contacted portions of the substrate (which act as a cathodeduring the plating operation) when an appropriate potential and/orcurrent are supplied.

An example of a CC mask and CC mask plating are shown in FIGS. 1A-1C.FIG. 1A shows a side view of a CC mask 8 consisting of a conformable ordeformable (e.g. elastomeric) insulator 10 patterned on an anode 12. Theanode has two functions. FIG. 1A also depicts a substrate 6 separatedfrom mask 8. One is as a supporting material for the patterned insulator10 to maintain its integrity and alignment since the pattern may betopologically complex (e.g., involving isolated “islands” of insulatormaterial). The other function is as an anode for the electroplatingoperation. CC mask plating selectively deposits material 22 onto asubstrate 6 by simply pressing the insulator against the substrate thenelectrodepositing material through apertures 26 a and 26 b in theinsulator as shown in FIG. 1B. After deposition, the CC mask isseparated, preferably non-destructively, from the substrate 6 as shownin FIG. 1C. The CC mask plating process is distinct from a“through-mask” plating process in that in a through-mask plating processthe separation of the masking material from the substrate would occurdestructively. As with through-mask plating, CC mask plating depositsmaterial selectively and simultaneously over the entire layer. Theplated region may consist of one or more isolated plating regions wherethese isolated plating regions may belong to a single structure that isbeing formed or may belong to multiple structures that are being formedsimultaneously. In CC mask plating as individual masks are notintentionally destroyed in the removal process, they may be usable inmultiple plating operations.

Another example of a CC mask and CC mask plating is shown in FIGS.1D-1F. FIG. 1D shows an anode 12′ separated from a mask 8′ thatcomprises a patterned conformable material 10′ and a support structure20. FIG. 1D also depicts substrate 6 separated from the mask 8′. FIG. 1Eillustrates the mask 8′ being brought into contact with the substrate 6.FIG. 1F illustrates the deposit 22′ that results from conducting acurrent from the anode 12′ to the substrate 6. FIG. 1G illustrates thedeposit 22′ on substrate 6 after separation from mask 8′. In thisexample, an appropriate electrolyte is located between the substrate 6and the anode 12′ and a current of ions coming from one or both of thesolution and the anode are conducted through the opening in the mask tothe substrate where material is deposited. This type of mask may bereferred to as an anodeless INSTANT MASK™ (AIM) or as an anodelessconformable contact (ACC) mask.

Unlike through-mask plating, CC mask plating allows CC masks to beformed completely separate from the fabrication of the substrate onwhich plating is to occur (e.g. separate from a three-dimensional (3D)structure that is being formed). CC masks may be formed in a variety ofways, for example, a photolithographic process may be used. All maskscan be generated simultaneously, prior to structure fabrication ratherthan during it. This separation makes possible a simple, low-cost,automated, self-contained, and internally-clean “desktop factory” thatcan be installed almost anywhere to fabricate 3D structures, leaving anyrequired clean room processes, such as photolithography to be performedby service bureaus or the like.

An example of the electrochemical fabrication process discussed above isillustrated in FIGS. 2A-2F. These figures show that the process involvesdeposition of a first material 2 which is a sacrificial material and asecond material 4 which is a structural material. The CC mask 8, in thisexample, includes a patterned conformable material (e.g. an elastomericdielectric material) 10 and a support 12 which is made from depositionmaterial 2. The conformal portion of the CC mask is pressed againstsubstrate 6 with a plating solution 14 located within the openings 16 inthe conformable material 10. An electric current, from power supply 18,is then passed through the plating solution 14 via (a) support 12 whichdoubles as an anode and (b) substrate 6 which doubles as a cathode. FIG.2A, illustrates that the passing of current causes material 2 within theplating solution and material 2 from the anode 12 to be selectivelytransferred to and plated on the cathode 6. After electroplating thefirst deposition material 2 onto the substrate 6 using CC mask 8, the CCmask 8 is removed as shown in FIG. 2B. FIG. 2C depicts the seconddeposition material 4 as having been blanket-deposited (i.e.non-selectively deposited) over the previously deposited firstdeposition material 2 as well as over the other portions of thesubstrate 6. The blanket deposition occurs by electroplating from ananode (not shown), composed of the second material, through anappropriate plating solution (not shown), and to the cathode/substrate6. The entire two-material layer is then planarized to achieve precisethickness and flatness as shown in FIG. 2D. After repetition of thisprocess for all layers, the multi-layer structure 20 formed of thesecond material 4 (i.e. structural material) is embedded in firstmaterial 2 (i.e. sacrificial material) as shown in FIG. 2E. The embeddedstructure is etched to yield the desired device, i.e. structure 20, asshown in FIG. 2F.

Various components of an exemplary manual electrochemical fabricationsystem 32 are shown in FIGS. 3A-3C. The system 32 consists of severalsubsystems 34, 36, 38, and 40. The substrate holding subsystem 34 isdepicted in the upper portions of each of FIGS. 3A to 3C and includesseveral components: (1) a carrier 48, (2) a metal substrate 6 onto whichthe layers are deposited, and (3) a linear slide 42 capable of movingthe substrate 6 up and down relative to the carrier 48 in response todrive force from actuator 44. Subsystem 34 also includes an indicator 46for measuring differences in vertical position of the substrate whichmay be used in setting or determining layer thicknesses and/ordeposition thicknesses. The subsystem 34 further includes feet 68 forcarrier 48 which can be precisely mounted on subsystem 36.

The CC mask subsystem 36 shown in the lower portion of FIG. 3A includesseveral components: (1) a CC mask 8 that is actually made up of a numberof CC masks (i.e. submasks) that share a common support/anode 12, (2)precision X-stage 54, (3) precision Y-stage 56, (4) frame 72 on whichthe feet 68 of subsystem 34 can mount, and (5) a tank 58 for containingthe electrolyte 16. Subsystems 34 and 36 also include appropriateelectrical connections (not shown) for connecting to an appropriatepower source for driving the CC masking process.

The blanket deposition subsystem 38 is shown in the lower portion ofFIG. 3B and includes several components: (1) an anode 62, (2) anelectrolyte tank 64 for holding plating solution 66, and (3) frame 74 onwhich the feet 68 of subsystem 34 may sit. Subsystem 38 also includesappropriate electrical connections (not shown) for connecting the anodeto an appropriate power supply for driving the blanket depositionprocess.

The planarization subsystem 40 is shown in the lower portion of FIG. 3Cand includes a lapping plate 52 and associated motion and controlsystems (not shown) for planarizing the depositions.

Another method for forming microstructures from electroplated metals(i.e. using electrochemical fabrication techniques) is taught in U.S.Pat. No. 5,190,637 to Henry Guckel, entitled “Formation ofMicrostructures by Multiple Level Deep X-ray Lithography withSacrificial Metal layers. This patent teaches the formation of metalstructure utilizing mask exposures. A first layer of a primary metal iselectroplated onto an exposed plating base to fill a void in aphotoresist, the photoresist is then removed and a secondary metal iselectroplated over the first layer and over the plating base. Theexposed surface of the secondary metal is then machined down to a heightwhich exposes the first metal to produce a flat uniform surfaceextending across the both the primary and secondary metals. Formation ofa second layer may then begin by applying a photoresist layer over thefirst layer and then repeating the process used to produce the firstlayer. The process is then repeated until the entire structure is formedand the secondary metal is removed by etching. The photoresist is formedover the plating base or previous layer by casting and the voids in thephotoresist are formed by exposure of the photoresist through apatterned mask via X-rays or UV radiation.

A need remains for enhanced build operation diagnostics. A further needremains for minimizing wasted time, effort, and/or material.

SUMMARY OF THE INVENTION

It is an object of various aspects of the invention to provide amicroscale or mesoscale fabrication process that provides enhanced buildproblem diagnostics.

It is an object of various aspects of the invention to provide amicroscale or mesoscale fabrication process that provides for enhanceddetermination of the successful or unsuccessful completion of attemptedbuild processes.

It is an object of various aspects of the invention to provide amicroscale or mesoscale fabrication process that includes more timelyrecognition when a faulty build process has occurred or is believedlikely to have occurred.

It is an object of various aspects of the invention to provide amicroscale or mesoscale fabrication process that reduces wastedfabrication time when a faulty build process has occurred or is believedlikely to have occurred.

It is an object of various aspects of the invention to provide amicroscale or mesoscale fabrication process that reduces wastedfabrication effort when a faulty build process has occurred or isbelieved likely to have occurred.

Other objects and advantages of various aspects of the invention will beapparent to those of skill in the art upon review of the teachingsherein. The various aspects of the invention, set forth explicitlyherein or otherwise ascertained from the teachings herein, may addressone or more of the above objects alone or in combination, oralternatively may address some other object of the invention ascertainedfrom the teachings herein. It is not necessarily intended that allobjects be addressed by any single aspect of the invention even thoughthat may be the case with regard to some aspects.

A first aspect of the invention provides an electrochemical fabricationprocess for producing a three-dimensional structure from a plurality ofadhered layers, the process including: (A) selectively depositing atleast a portion of a layer onto the substrate, wherein the substrate mayinclude previously deposited material; (B) forming a plurality of layerssuch that successive layers are formed adjacent to and adhered topreviously deposited layers, wherein said forming includes repeatingoperation (A) a plurality of times; wherein at least a plurality of theselective depositing operations include: (1) adhering a mask to orlocating a preformed mask in contact with or in proximity to asubstrate; (2) in presence of a plating solution, conducting an electriccurrent between an anode and the substrate through the at least oneopening in the mask, such that a selected deposition material isdeposited onto the substrate to form at least a portion of a layer; and(3) removing the mask from the substrate; wherein during one or morelayer formation processes or after one or more layer formation processesat least one inspection occurs that is capable of identifying aplurality of process failures and wherein at least one of any failuresis correlated to a potential corrective action and at least onecorrective action is taken to allow successful fabrication of thestructure to continue.

A second aspect of the invention provides an electrochemical fabricationprocess for producing a three-dimensional structure from a plurality ofadhered layers, the process including: (A) selectively depositing atleast a portion of a layer onto the substrate, wherein the substrate mayinclude previously deposited material; (B) forming a plurality of layerssuch that successive layers are formed adjacent to and adhered topreviously deposited layers, wherein said forming includes repeatingoperation (A) a plurality of times; wherein at least a plurality of theselective depositing operations include: (1) adhering a mask to orlocating a preformed mask in contact with or in proximity to asubstrate; (2) in presence of a plating solution, conducting an electriccurrent between an anode and the substrate through the at least oneopening in the mask, such that a selected deposition material isdeposited onto the substrate to form at least a portion of a layer; and(3) removing the mask from the substrate; wherein during, or after,formation of a given layer, the layer is inspected or formationparameters are compared to anticipated parameter values such that adetermination concerning the existence of a plurality of potential buildproblems is made wherein if it is determined that the layer was notformed correctly, at least a portion of material deposited inassociation with the layer is removed and replacement material isdeposited.

A third aspect of the invention provides a process for forming amultilayer three-dimensional structure, including: (A) forming andadhering a layer of material to a substrate, wherein the substrate mayinclude previously formed layers; (B) repeating the forming and adheringoperation of (a) a plurality of times to build up a three-dimensionalstructure from a plurality of adhered layers; wherein the formation ofeach of at least a plurality of layers, includes: (1) obtaining aselective pattern of deposition of a first material having voids,including at least one of: (a) selectively depositing a first materialonto the substrate such that at least one void remains, wherein thedepositing includes: (i) adhering a mask and a surface of the substratetogether or bringing a preformed mask into contact with or in proximityto the substrate in preparation for depositing a first material; (ii)depositing the first material onto the substrate with the mask in place;(iii) separating the mask and the substrate to expose the at least onevoid; or (b) depositing a first material onto the substrate andselectively etching the deposit of the first material to form voidstherein, wherein the etching includes: (i) adhering a mask and a surfaceof the deposited first material together or bring a preformed mask intocontact with or in proximity to the substrate; (ii) etching, with themask in place, into the first material to form at least one void; (iii)separating the mask and the substrate; and (2) depositing a secondmaterial into the at least one void, and wherein during, or after,formation of a given layer, the layer is inspected, or formationparameters are compared to anticipated parameter values, such that if itis determined that the layer was not formed correctly, at least aportion of material deposited in association with the layer is removedand replacement material is deposited.

A fourth aspect of the invention provides an electrochemical fabricationprocess for producing a three-dimensional structure from a plurality ofadhered layers, the process including: (A) selectively depositing atleast a portion of a layer onto the substrate, wherein the substrate mayinclude previously deposited material; (B) forming a plurality of layerssuch that successive layers are formed adjacent to and adhered topreviously deposited layers, wherein said forming includes repeatingoperation (A) a plurality of times; wherein at least a plurality of theselective depositing operations include: (1) adhering a mask to orlocating a preformed mask in contact with or in proximity to asubstrate; (2) depositing onto the substrate a desired material to format least a portion of a layer; and (3) removing the mask from thesubstrate; wherein during one or more layer formation processes or afterone or more layer formation processes at least one inspection occursthat is capable of identifying a plurality of process failures andwherein at least one of any failures is correlated to a potentialcorrective action and at least one corrective action is taken to allowsuccessful fabrication of the structure to continue.

A fifth aspect of the invention provides an electrochemical fabricationprocess for producing a three-dimensional structure from a plurality ofadhered layers, the process including: (A) selectively depositing atleast a portion of a layer onto the substrate, wherein the substrate mayinclude previously deposited material; (B) forming a plurality of layerssuch that successive layers are formed adjacent to and adhered topreviously deposited layers, wherein said forming includes repeatingoperation (A) a plurality of times; wherein at least a plurality of theselective depositing operations include: (1) adhering a mask to orlocating a preformed mask in contact with or in proximity to asubstrate; (2) depositing onto the substrate a desired material to format least a portion of a layer; and (3) removing the mask from thesubstrate; wherein during, or after, formation of a given layer, thelayer is inspected or formation parameters are compared to anticipatedparameter values such that a determination concerning the existence of aplurality of potential build problems is made wherein if it isdetermined that the layer was not formed correctly, at least a portionof material deposited in association with the layer is removed andreplacement material is deposited.

Further aspects of the invention will be understood by those of skill inthe art upon reviewing the teachings herein. Other aspects of theinvention may involve combinations of the above noted aspects of theinvention. Other aspects of the invention may involve apparatus that canbe used in implementing one or more of the above method aspects of theinvention. These other aspects of the invention may provide variouscombinations of the aspects presented above as well as provide otherconfigurations, structures, functional relationships, and processes thathave not been specifically set forth above.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C schematically depict side views of various stages of a CCmask plating process, while FIGS. 1D-G schematically depict a side viewsof various stages of a CC mask plating process using a different type ofCC mask.

FIGS. 2A-2F schematically depict side views of various stages of anelectrochemical fabrication process as applied to the formation of aparticular structure where a sacrificial material is selectivelydeposited while a structural material is blanket deposited.

FIGS. 3A-3C schematically depict side views of various examplesubassemblies that may be used in manually implementing theelectrochemical fabrication method depicted in FIGS. 2A-2F.

FIGS. 4A-4I schematically depict the formation of a first layer of astructure using adhered mask plating where the blanket deposition of asecond material overlays both the openings between deposition locationsof a first material and the first material itself

FIG. 5 illustrates a block diagram of rework elements of a firstgeneralized embodiment.

FIG. 6 provides a block diagram of rework elements of a secondgeneralized embodiment.

FIGS. 7A-7B provides a flowchart of a third generalized embodiment wherebuild operations are specified along with failure or problem recognitionand corrective action decisions and corrective action implementation.

FIG. 8A-8B provides a flowchart of a fourth generalized embodiment whereit is assumed all layers have been formed and that post processingoperations are to be performed and that failure or problem recognitionis made during post processing operations and that appropriatecorrective actions are taken.

FIG. 9A provides a block diagram listing examples of build problems thatmay be recognized, monitored or detected as part of an embodiment of thepresent invention.

FIG. 9B provides examples of various rework or corrective actionoperations that may be used in getting the building operations back ontrack when build problems are discovered.

DETAILED DESCRIPTION

FIGS. 1A-1G, 2A-2F, and 3A-3C illustrate various features of one form ofelectrochemical fabrication that are known. Other electrochemicalfabrication techniques are set forth in the '630 patent referencedabove, in the various previously incorporated publications, in variousother patents and patent applications incorporated herein by reference,still others may be derived from combinations of various approachesdescribed in these publications, patents, and applications, or areotherwise known or ascertainable by those of skill in the art from theteachings set forth herein. All of these techniques may be combined withthose of the various embodiments of various aspects of the invention toyield enhanced embodiments. Still other embodiments may be derived fromcombinations of the various embodiments explicitly set forth herein.

FIGS. 4A-4I illustrate various stages in the formation of a single layerof a multi-layer fabrication process where a second metal is depositedon a first metal as well as in openings in the first metal where itsdeposition forms part of the layer. In FIG. 4A, a side view of asubstrate 82 is shown, onto which patternable photoresist 84 is cast asshown in FIG. 4B. In FIG. 4C, a pattern of resist is shown that resultsfrom the curing, exposing, and developing of the resist. The patterningof the photoresist 84 results in openings or apertures 92(a)-92(c)extending from a surface 86 of the photoresist through the thickness ofthe photoresist to surface 88 of the substrate 82. In FIG. 4D, a metal94 (e.g. nickel) is shown as having been electroplated into the openings92(a)-92(c). In FIG. 4E, the photoresist has been removed (i.e.chemically stripped) from the substrate to expose regions of thesubstrate 82 which are not covered with the first metal 94. In FIG. 4F,a second metal 96 (e.g., silver) is shown as having been blanketelectroplated over the entire exposed portions of the substrate 82(which is conductive) and over the first metal 94 (which is alsoconductive). FIG. 4G depicts the completed first layer of the structurewhich has resulted from the planarization of the first and second metalsdown to a height that exposes the first metal and sets a thickness forthe first layer. In FIG. 4H the result of repeating the process stepsshown in FIGS. 4B-4G several times to form a multi-layer structure areshown where each layer consists of two materials. For most applications,one of these materials is removed as shown in FIG. 4I to yield a desired3-D structure 98 (e.g. component or device).

The various embodiments, alternatives, and techniques disclosed hereinmay form multi-layer structures using a single patterning technique onall layers or using different patterning techniques on different layers.For example, different types of patterning masks and masking techniquesmay be used or even techniques that perform direct selective depositionswithout the need for masking. Proximity masks and masking operations(i.e. operations that use masks that at least partially selectivelyshield a substrate by their proximity to the substrate even if contactis not made) may be used, and adhered masks and masking operations(masks and operations that use masks that are adhered to a substrateonto which selective deposition or etching is to occur as opposed toonly being contacted to it) may be used. Patterning operations may beused in selectively depositing material and/or may be used in theselective etching of material. Selectively etched regions may beselectively filled in or filled in via blanket deposition, or the like,with a different desired material. In some embodiments, thelayer-by-layer build up may involve the simultaneous formation ofportions of multiple layers. In some embodiments, depositions made inassociation with some layer levels may result in depositions to regionsassociated with other layer levels. Such use of selective etching andinterlaced material deposited in association with multiple layers aredescribed in U.S. patent application Ser. No. 10/434,519, by Smalley,and entitled “Methods of and Apparatus for Electrochemically FabricatingStructures Via Interlaced Layers or Via Selective Etching and Filling ofVoids layer elements” which is hereby incorporated herein by referenceas if set forth in full.

For example, the enhanced contact mask mating techniques may be used incombination with conformable contact masks and/or non-conformablecontact masks and masking operations on some layers while other layersmay be formed using contact masks. As another example, formation of somelayers may involve the selective deposition of one or more materials,while the formation of other layers may involve selective etching ofmaterials, while the formation of still other layers involves the bothselective deposition and selective etching.

U.S. patent Application Nos. 60/379,132 and 10/434,494 both by Zhang andCohen, and both entitled “Methods and Apparatus for MonitoringDeposition Quality During Conformable Contact Mask Plating Operations”are hereby incorporated herein by reference as if set forth in full.

The '494 application teaches that measurements of cell voltage duringplating can provide information on several different platingconditions/results and that for each deposition by conformable contactmasking, the deposition process can be monitored wherein problems may berecognized during deposition or after the completion of a deposition. Italso teaches that based on an analysis of the resulting voltage curvesin comparison to an anticipated curve or in comparison to a predefinedacceptability or rejection criteria, a decision can be made as towhether or not the formation process can continue on course, whether theprocess should be aborted, or whether some form of remedial orcorrective action should be taken.

The '494 application further teaches that for each deposition byconformable contact masking, the deposition process can be monitoredwherein problems may be recognized during deposition or after thecompletion of a deposition. Based on an analysis of the resultingvoltage curves in comparison to an anticipated curve or in comparison toa predefined acceptability or rejection criteria, a decision can be madeas to whether or not the formation process can continue on course,whether the process should be aborted, or whether some form of remedialor corrective action should be taken. Problem detection may occur byoperator review and analysis of one or more monitored electric signals(e.g. voltages), by automated system recognition, or by a combination ofthe two. Depending on the level of automation of the system and thebelieved severity of the problem, remedial action may be performedmanually by an operator or under automated system control and it mayinvolve a number of different operations:

(1) Visual or secondary inspections may be performed to confirm that aproblem occurred or to determine the severity of the problem so as toaid in making decisions on the most appropriate forms of additionalremedial action to take, if any;

(2) If the offending deposition is still underway at the time of problemrecognition,

i. it may be aborted; or

ii. it may be allowed to continue for a time;

(3) One or more additional depositions may be allowed to occur (e.g. toensure full lateral support of the deposited structure)

(4) A trimming process (e.g. planarization process by mechanical lappingor by CMP) may be implemented to remove all of, or just a portion of,the offending deposit.

(5) Complete or partial redeposition of the offending pattern may beundertaken

i. the same mask may be used in one or more subsequent attempts; or

ii an alternate mask may be used on one or more subsequent attempts; and

(6) If an optimal redeposition cannot be obtained, within a certainnumber of attempts, an automated system may be programmed to interruptthe formation process, pending operator intervention or to continue withthe formation process while leaving behind an appropriate log of theissues encountered and remedial steps attempted.

The '494 application even further teaches that various embodiments maybe implemented using a single rejection criteria (e.g. shortingrecognition) or using multiple rejection criteria. Each rejectioncriteria used may result in execution of the same remedial process ordifferent rejection criteria may result in implementation of differentremedial actions. In some embodiments remedial action may involve eachof operations (1) to (6) as noted above. In other embodiments only asubset of operations (1) to (6) may be used, for example (2)(ii)followed by (4) followed by (5)(b), and then by (6), if necessary. Eachtime operation (6) is encountered when a certain number of attempts havenot yet been made, the remedial actions may be different. In someembodiments, if a problem associated with a given layer is believed tobe the result of a problem on a previous layer or if the remedial stepstaken on the present layer may have negatively affected one or moreprevious layers, not only may one or more depositions associated withthe present layer be trimmed away, but material may be trimmed from oneor more previous layers. Redepositions of material for the present layerand for any previous layers of removed material may also be performed.In some embodiments trimming operations may involve anodic etching asopposed to or in addition to other trimming processes.

Various embodiments of the invention of the present application extendthe embodiments disclosed in the '494 application, provide for detectionof other build process failings, and/or provide for the taking ofdifferent or additional remedial actions. Various other problemrecognition possibilities and remedial operation possibilities, andcombinations will be apparent to those of skill in the art after reviewof the teachings herein.

FIG. 5 illustrates a block diagram of rework elements of a firstgeneralized embodiment. The rework elements may be considered to startwith the recognition of a build problem as indicated by block 102. Afterrecognition of the problem, the process moves forward to block 104 whichcalls for the taking of one or more actions based, at least in part, onthe occurrence of the problem. The remedial actions are taken to allowthe building of the structure to continue toward completion withoutneeding to restart the formation of the structure from the beginning. Arecognized problem may be one or more of those set forth in elements502-558 of FIG. 9 or it may be some other problem and the remedialaction may be one or more of the actions set forth in elements 602-638of FIG. 9 or it may be some other action.

FIG. 6 provides a block diagram of rework elements of a secondgeneralized embodiment. The rework elements start with monitoringselected build operations as indicated by block 202. The monitoring mayoccur during performance of a selected build operation or afterperformance of the operation. The monitoring may be appropriate fordetermining one or more of the build problems set forth in elements502-558 of FIG. 9 or may be appropriate for ascertaining some otherproblem. Next, a problem or failure in the build process or in theresult of the build process is recognized as indicated block 204. Insome alternatives, it may not be necessary to recognize the existence ofa particular or specific problem but simply to conclude that a certainamount or type of rework is necessary or is to be performed. Therecognition of the problem may occur in a variety of ways. In someimplementations it may be recognized through operator inspection of thestructure or data recorded during the process while in otherimplementations recognition may occur via an automated process. Next,possibly based on specific details of the failure, potential correctiveaction options are determined and their applicability is evaluated asindicated by block 206 and thereafter decisions on the corrective actionor actions to take are made as indicated by block 208. Finally thecorrective actions are taken as indicated in block 210.

FIGS. 7A-7B provide a flowchart of a third generalized embodiment wherebuild operations are specified along with failure or problem recognitionand corrective action decisions and corrective action implementation.Elements AAA, BBB, and CCC are simply used to connect the process flowbetween the first half of the flow chart shown in FIG. 7A and the secondhalf of the flow chart shown in FIG. 7B.

The process of FIGS. 7A and 7B begins with element 302 based on thedefinitions provided in block 300. From element 302 the process proceedsto block 304, which calls for the supplying of a substrate on which astructure will be formed. The substrate may take any of a variety offorms. For example, it may be a conductive material, a dielectricmaterial such as a polymer or a ceramic, it may be a substrate thatincludes a preexisting structure such as an integrated circuit amicrodevice formed via an EFAB building process or via a silicon basedMEMS process.

The process then proceeds to elements 306, 308 and 310 whichrespectively call for setting variable n to 1, variable o_(n) to 1 andsetting all variables c_(m)o_(n) to 1.

The process then moves forward to decision block 312 which inquires asto whether or not the performance of operation o_(n) will be monitored.If the answer is no the process moves forward to element 322 which callsfor the performance o_(n) after which the process moves forward toelement 324 which will be discussed hereinafter.

If the answer to the inquiry of block 312 is “yes” the process movesforward to element 314 which calls for the monitoring and performance ofoperation o_(n). During the monitoring and performance of operation 314the process moves forward to element 316 which inquires as to whether ornot a failure has occurred. If it has, the process moves forward toelement 332 which will be discussed hereinafter. If no failure hasoccurred the process moves forward to decision block 318 which inquiresas to whether operation o_(n) has been completed. If the answer to thisinquiry is “no” the process loops back to element 314. If the answer tothis inquiry is “yes” the process moves forward to decision block 324which inquires as to whether or not a failure analysis is to beperformed. If the answer to this inquiry is no the process moves forwardto element 362 which will be discussed hereinafter. If the answer tothis inquiry is “yes” the process moves to element 326 which calls forthe performance of the failure analysis. Next the process moves forwardto decision block 328 which inquires as to whether or not a failure hasoccurred. If the answer to this question is “no” the process movesforward to element 362 but if the answer is “yes” the process movesforward to decision block 332.

Decision block 332 inquires as to whether any corrective actions existfor correcting the failure. If the answer is “no” the process proceedsto element 334 which calls for the end of the build process or at leasta holding of the process to wait for operator input. If the answer tothe inquiry of decision block 332 is “yes” the process moves forward todecision block 338 which inquires as to whether or not the n^(th) typecorrection action for operation o_(n) is greater than a final n^(th)type corrective action associated with o_(n). If the answer to thisinquiry is “yes” the process moves forward to element 346 and theprocess either ends or is put on hold for further operator input. If theanswer to the inquiry of decision block 338 is “no” the process movesforward to block 352 which calls for the performance of a correctiveaction or actions as well as the setting of layer variable n andoperation o_(n) to appropriate values. The value of n and the value ofo_(n) may change as a result of the corrective actions for variousreasons, for example, as a result of the removal of deposits associatedwith previous operations on layer n or even the removal of depositsassociated with previous layers.

From block 352 the process moves forward to block 354 which calls forsetting variable c_(m)o_(n) to a value c_(m+1)o_(n). From block 354 theprocess moves forward to block 364.

As indicated previously, “no” responses to the decision blocks ofelements 324 and 328 cause the process to move forward to block 362.Block 362 calls for incrementing variable o_(n) to a value of o_(n+1).

From element 362 the process moves forward to decision block 364 whichinquires as to whether or not o_(n) is greater than O_(n). If the answerto this inquiry is “no” the process loops back to block 312 whereas ifthe answer to this inquiry is “yes” the process moves forward to block366. Block 366 calls for incrementing the variable n to a value of n+1.Then the process moves forward to decision block 368 which inquires asto whether variable n is greater than N (i.e. the last layer of thestructure being built). If the answer to the inquiry of decision block368 is “no” the process loops back to block 308 whereas if the answer tothe inquiry is “yes” the process moves forward to terminator 372 whichcalls for the end of the layer formation process as the result of asuccessful building operation.

In some embodiments the process of forming a structure component ordevice may not actually be completed with the reaching of terminator 372as various post processing (i.e. post layer formation processing)operations may need to occur, for example, releasing the formedstructure from any sacrificial material or potentially from thesubstrate itself, heat treating the structure to improve interlayadhesion, dicing individual structures from one another, and the like.

Various alternatives to the embodiment of FIGS. 7A and 7B are possible.In some embodiments, the process flow may be simplified based onpredetermined decisions as to what process alternatives are available.In some alternatives, failures may occur only in association withselected die that are being simultaneously formed and thus the buildprocess may continue when a failure occurs by simply creating a data logof which dies have failed and/or which dies remain good. The number offailed die may be tracked and if the failure level is excessive, one ormore layers of material may be removed (i.e. the process may be pushedback to a point where the failure level is acceptable, possibly evenwith some room to spare for subsequent failures) and the layer formationprocess reinitiated from the lower layer number in hopes of achieving asuccessful build with adequate yield.

FIGS. 8A and 8B provide a flowchart of a fourth generalized embodimentwhere it is assumed all layers have been formed and that post processingoperations are to be performed and that failure or problem recognitionis made during post processing operations and that appropriatecorrective actions are taken. Elements AAA-GGG as shown in both FIGS. 8Aand 8B are simply used to connect the process flow between the firsthalf of the flow chart shown in FIG. 8A and the second half of the flowchart shown in FIG. 8B.

The process of FIGS. 8A and 8B begins with element 402 which calls forthe starting of the process based on a completed structure that is goingto undergo post processing (i.e. a structure which has all layersalready formed). Block 402 takes as an input various definitions as setforth in block 400.

From Block 402 the process moves forward to block 404 which calls forsetting a variable ppo equal to 1 and then proceeds to block 406 whichcalls for setting all values of the variable c_(m)ppo equal to 1. Fromblock 406 the process proceeds to decision block 408 which inquires asto whether operation ppo will be monitored during its performance. Ifthe answer is “no” the process moves forward to element 410 which callsfor the performance of the post processing operation ppo. If the answerto the inquiry of block 408 is “yes” the process moves forward toelement 412 which calls for monitoring and performance of process ppo.During the performance of process ppo block 414 is encountered whichinquires as to whether the monitoring has resulted in the detection of afailure. If the answer to this inquiry is “yes” the process movesforward to decision block 428 which will be described hereinafter. Ifthe answer to the inquiry of block 414 is “no” the process moves forwardto decision block 416 which inquires to whether or not operation ppo_(n)has been completed.

If the inquiry of element 416 produces a “no” response the process loopsback to element 412. If the inquiry produces a “yes” response theprocess moves forward to decision block 418. Decision block 418 inquiresas to whether a failure analysis is to be performed. If the answer is“no” the process moves forward to block 422 which will be describedhereinafter.

If block 418 produces a “yes” response the process moves forward toblock 424 which calls for the performance of the failure analysis afterwhich the process moves forward to decision block 426 which inquires asto whether a failure has occurred. If a failure has not occurred theprocess moves forward to block 422 which calls for incrementing thevalue of variable ppo to ppo+1 after which the process moves forward toelement 452 which will be described hereinafter. If block 426 produces a“yes” response the process moves forward to block 428 which inquires asto whether or not corrective actions exist for the problem or failureencountered. If block 428 produces a negative response the process movesforward to terminator 432 which calls for the end of the process or atleast holding for operator input. If the inquiry of block 428 produces apositive response the process moves forward to decision block 434 whichinquires as to whether a m^(th) corrective action for post processingoperation ppo is greater than a final M^(th) corrective action that maybe taken based on a failure associated with process PPO.

If the inquiry produces a positive response the process moves forward toterminator 436 which calls for the end of the process or at least aholding of the process until operator input can be obtained. If theinquiry of block 434 produces a negative response the process movesforward to block 438 which calls for the performance of correctiveactions and possibly the setting of a variable n and a variable o_(n) toappropriate values. The variable n may be a layer number variable ando_(n) may be operation number associated with that layer number. Thesevalues may need to be set based on a need to go back and perform one ormore operations associated with layer formation. Such a need for goingback to perform additional layer formation operations may result from acorrective action that removes one or more layers from what was acompleted structure. Block 438 also calls for setting ppo to anappropriate value. This appropriate value may, for example, be anincrementing of ppo by one or retaining ppo at its current value.

From block 438 the process moves forward to decision block 442 whichinquires as to whether or not the corrective action resulted in a needto reform one or more layers. If the inquiry produces a “no” responsethe process moves forward to element 450 which calls for incrementingthe m^(th) type correction action variable for operation ppo by 1. Fromblock 450 the process moves forward to decision block 452 which inquiresas to whether or not the current post processing operation variable ppohas a value that is greater than a final post processing operation valuePPO. If inquiry 452 produces a negative response the process loops backto block 408. If however, block 452 produces a positive response theprocess moves to terminator 454 and the process ends. Turning back todecision block 442 if a positive response is produced the process movesforward to decision block 444 which inquires as to whether or not thestructure needs to be surrounded by a conductive sacrificial material.This requirement may result from an earlier post processing operationwhere the sacrificial material was removed but since further layeroperations are necessary it may be required to reinsert the sacrificialmaterial. If this inquiry produces a negative response the process movesup to block 448 which will be described hereinafter. And if the inquiryproduces a positive response the process moves forward to block 446.

Block 446 calls for the deposition of a conductive sacrificial material.After which the process moves forward to block 448 which calls for theperformance of the required layer build up operations which, forexample, may be incremented by temporarily diverting the present processto block 364 of FIG. 7, completing that process of FIG. 7 and thancoming back to block 448. After the operation or operations of block 448are performed the process loops back to block 404 where post processingoperations may be initiated from their original starting point.

In some embodiments, however, not all post processing operations mayneed to be performed again and in those embodiments the post processingoperations may loop back to block 406 or even block 408. Various otheralternatives will be apparent to those of skill in the art upon reviewof the teachings herein.

FIG. 9A provides a block diagram listing examples of build problems thatmay be recognized, monitored or detected as part of an embodiment of thepresent invention while FIG. 9B provides examples of various rework orcorrective action operations that may be used in getting the buildingoperations back on track when build problems are discovered.

A flash deposit, block 502 of FIG. 9A, if it occurs, typically occursduring selective deposition where the seating of the mask to thesubstrate is imperfect and material not only becomes deposited in theopen regions or voids of the mask but also between the shielding portionof the mask and the substrate. Flash can be hard to detect after anadditional material is overlaid on the selectively deposited material.Prior to depositing an additional material visual inspection (e.g. basedon color differences under selected light) may be used to determine thepresence of flash and a non-aggressive etch may be used to clean uprelatively thin flash or flash-like deposits. It is possible thatspectroscopic analysis based on light reflected from regions that are tobe open may be used to detect regions of flash. Such a visual orspectroscopic analysis may be based on known regions of each type ofmaterial from a previous layer along with regions on the present layerwhere the material is to exist. A complement of a Boolean union of theregions associated with the selectively deposited material would producethe regions where the selectively deposited material should not existand thus it may be used in determining if the material hasinappropriately turned up. Such information may then be used intriggering a blanket or patterned etching with the intent to remove someor all of the flash deposit without excessive impact on the regionswhere no flash deposit occurred. The etching operation may, for example,be of the chemical or electrochemical type and it may be selective ornon-selective to the material of the flash deposit. In otherembodiments, it may be possible to detect flash based on a precisethicknesses measurement. In still other embodiments, it may be possibleto infer the existence of flash based on monitoring electricalcharacteristics as noted in U.S. patent application Ser. No. 10/434,494referenced previously.

In some embodiments, the rework operation selected for overcomingflashed based failures may be planarization of the previous layer andsubsequent redeposition. In variations of these embodimentsplanarization of the deposit could occur without performing additionaldeposits while in other variations additional material may be deposited(e.g. via a blanket deposit) if there is a planarizing without ashielding material might result in tearing off relatively large chunksof the first material and getting them inadvertently embedded into thelower layer (i.e. the previous layer).

Another possible build defect is inadequate layer thickness. This defectmay result from various causes one of which is shorting and another ofwhich is non-uniform deposition (e.g. some layer portions havereasonably uniform excess thickness while others have reasonably uniformbut too little thickness). Inadequate layer thickness may be detected byphysical inspection or measurement. If it results from shorting, it maybe detected by monitoring deposition voltage as explained in the '494application. Shorting may be more of a problem associated with use ofcontact masks as opposed to adhered masks and more specifically withcontact masks use an anode as a support.

Inadequate layer thickness may be ascertained by making an absolutemeasurement of the thickness of the partially formed structure relativeto its substrate or by a relative measurement of profile (e.g. using aprofilometer). Some measurements may be made by dragging a probe acrossa surface or by contacting discrete points. In the case of using anadhered mask it may be possible to make measurements without removingthe masking material. This may also be possible in some embodimentswhere anodeless contact masks are used. In some embodiments detectionmay be made optically, e.g. by focusing an image at two height levelswhere a translation or required focusing change may be correlated to aheight differential.

In other embodiments detection of thin layers may be done on asingle-point basis or a multi-point basis where various portions of thelayer are checked. In particular when doing single-point or multi-pointchecking, the target locations may selected based on prior knowledge ofregions of the layer that are susceptible to under-plating (e.g. such asvery small areas).

In some embodiments indirect techniques may be used to detect inadequatelayer thickness. For example, a blanket deposition of a desiredthickness may be used and then a planarization operation used. After theplanarization operation, the first deposited material should be visiblein the desired pattern if it is not, it may be concluded that thedeposition was not thickness enough. The pattern recognition may beperformed manually or automatically by comparing images obtained byscanning to images generated from cross-sectional data and the like. Anydetected differences may result in rejection of the layer oralternatively they may be flagged as problem areas that will requiremanual inspection and approval prior to continuing with build operationsContrast difference is the difficulty in automatic and manual comparisonoperations. Contrast can be enhanced but selectively etching one of thematerials but it may not lead to desired surface finish and may resultin a need to perform additional planarization or polishing operations.

Reworking layers having deposits of inadequate thickness may beperformed in different ways. The offending layer may be completelyremoved (e.g. by planarizing or etching) and then it may be reformed.The layer may be planarized down until a thickness is reached that hasthe appropriate materials and patterns. If the planing results in alayer thickness that is only slightly less than that desired or if theaccuracy between the boundary of the present layer and the next layer isnot that critical, it may be possible simply form the next layer using aslightly enhanced thickness of the next layer. In other embodiments, themissing thickness of the layer may be made up for by forming a thinlayer having the same patterning as that of the just formed layer (i.e.the layer that had inadequate thickness that is too thin).

Smearing is a phenomenon that may occur when planarizing a layer havingmore than one material and particularly when those materials have asignificantly different hardness. The detection of smear can occur byvisually comparing an intended materials pattern with a detectedpattern. Smearing may manifests itself in two ways: (1) it may shift aboundary position between two materials or (2) it may make the edge gofrom regular to irregular. In some embodiments, the detection of smearmay occur by comparing detected visual images at first and secondplanarization levels when both levels are within the height of effectivedeposition of all materials. If boundary positions change, the changesmay be the result of the removal or creation of smear or that thedeposition height wasn't what was expected. If additional planing isnecessary to remove smear, layer height correction methods as discussedabove for correcting inadequate layer height may be used. Smear may alsobe removed or at least reduced by converting from harsh planarizationoperations to softer planarization operations or even to polishingoperations. Smear may also be reduced by use of relatively mild etchingoperations of either the chemical or electrochemical type that mayselective attack the smeared material or that may attack both materialssomewhat uniformly.

In other embodiments, smear may be detected by imaging the edges of aselective deposition prior to deposition of a second or subsequentmaterials and comparing those edges to edges obtained after depositionof the additional material or materials and after planarization.Differences between the images should yield smear based errors orfailures. In some embodiments the first image may be taken when thedeposition height is not yet completed but is believed to be reasonablyclose to the desired layer thickness.

Voids and Inclusions are another possible build process failure orproblem. One of the sources of voids is bubbles of air or hydrogen thatgets introduced in a deposit. Surface voids can be detected visuallyduring or after planarization and buried voids may be detected via x-rayimaging. In some embodiments, variations in plating voltage may beuseful in detecting or at least hinting at the presence of significantvoids (e.g. due to reduced cathode area). In some embodiments, if voidsare found in only one of the materials prior to planarization trimmingthe deposit to the layer thickness, a blanket deposition (or even aselective deposition) of the effected material may be used to fill thevoid after which additional planarization may trim the deposit down tothe desired layer thickness. If a void exists in more than one material,and the planarization operation has not brought the thickness of depositdown to the layer thickness level, a selective plating operation (e.g.using a mask similar to the original mask used on the layer) may be usedto fill the voids in one material and then a blanket or selectivedeposition may be used to fill the void in the another material. Thedepositions would be followed by further planarization. If theplanarization operation has already brought the deposit thickness downto the layer level, the above noted techniques may be used to fill thevoids wherein a choice to work with a slightly thinner than desiredlayer may be necessary or the depositions may need to build up thethickness sufficiently so that any tolerance in planarization will notresult in the wrong materials being located at some locations on thelayer.

Of course in other embodiments it may be appropriate to remove theentire layer and reapply it, particularly if structural strength iscritical and there is fear that a significant number of voids may existand may weaken the structure.

In still further embodiments, if the void or voids in a given materialon the bounding surface of one layer are determined to be overlaid bythe same material on the next layer, it may be appropriate to concludethat the existence of the void or voids are irrelevant since they wouldautomatically be taken care of by depositions made in association withthe next layer.

Inclusions may result from abrasives that are used in planarization,nodules from irregular plating, or from contaminants in the platingbaths. Detection of inclusions may be done via manual or automaticvisual inspection along with manual or automatic comparison to ananticipated image. Detection may occur via x-rays inspection or x-raytomography. Other embodiments may make use of probes that measurelocalized conductivity, capacitance, eddy currents, magneticpermeability. In still other embodiments, protruding inclusions may bedetected via profilometry, interferometry, or confocal microscopy

As with voids, if an inclusion is going to be trapped within thestructural material (e.g. because the next layer is going to overlie it)and the presence of the inclusion can be tolerated from a materialsproperty point of view, then these subsurface inclusions can be ignored.If the inclusion is in the sacrificial material and it's not in contactwith any structural material so that it will float off when it isreleased, it may be possible to again ignore the existence of theinclusion. If an inclusion were located within a small passage where itmight get stuck or other problematic area, it may be necessary to trimdown the layer to remove it. The trimming down may remove the entirelayer or it may remove only a portion of the layer where further layerbuild up or extension of the thickness of the next layer thickness willbe used to address the overall structural height issue.

In some embodiments inclusions may take the form of masking materialthat has broken off the mask when the mask was being removed orseparated from the deposit. In some circumstances these inclusions maynot be problematic even though they are dielectric. If they are smallenough, are not located in regions outside the structure, and are notlocated in regions that extend between structural and non-structuralmaterial, it is possible that they can be deposited over (e.g. viamushrooming of depositions) and be simply trapped within the structuralmaterial permanently or within the sacrificial material until releaseoccurs.

In some embodiments the inclusions may be removed by dissolving or thelike and then processes similar to those discussed above in associationwith handling voids may be used to address the problem.

Porosity is similar to voids but different in that it is not concernedwith specific voids but a generalized lack of density. Detection ofporosity may occur via visual inspection or via surface measurement. Inother embodiments porosity detection may occur via x-rays. In stillother embodiments porosity detection may be made via deviation from anexpected weight. In still other embodiments, x-ray images between an Nthlayer and an (N+1)th layer may be compared to help ascertain whetherporosity exists in the (N+1)th layer versus a previously formed layer.In some embodiments a conductivity measurement may be made to determineporosity or perhaps a conductivity comparison between successive layerscould be used.

In still other embodiments an ultrasonic probe may be used to find voidsand/or porosity and/or possible inclusions. These ultrasonic probeembodiments may operate with the partially formed structure in water (orother liquid) to improve the conduction of sonic vibrations. In stillother embodiments dye penetrant inspection may be used to identifyporosity or cracks and the like. In still other embodiments, magneticpermeability variations or eddy current detection may be used toidentify porosity or cracks and the like. In still other embodimentsvacuum or pressure may be used to draw or push a fluid through aconnected series of pores. In still other embodiments, a micro etch maybe used to remove smear (of structural material into small adjoiningvoids that might prevent detecting of the porosity.

Once porosity is detected it may be removed by removing the entire layeror the deposited portion of the layer and then allowing redeposition tooccur (hopefully under more favorable conditions)

Some additional examples of potential problems are set forth in FIG. 9A.These additional examples are believed to be largely self explanatoryand thus only a cursory description of some of them will be given below.These additional problems include (1) deposition of the wrong material,(2) geometric distortion due to stress or other build process failuresor due to the inadvertent use of inappropriate data or a mask indefining the deposition region; (3) adhesion failure or weakness betweena previously deposited layer and a subsequently deposited layer whichmay result from, for example, inadequate removal of oxides from thesurface of the previously formed layer; (4) electrical conductivefailure between layers which may result, for example, from inadequateremoval of oxides from the surface of the previously formed layer; (5)non-uniformity of layer thickness which may result from depositionirregularities, failure to control planarity during planarizationoperations; (6) mechanical properties out of specification which mayresult from a variety of problems, such as plating bath problems,inappropriate current control during plating, and the like; (7)electrical properties out of specification which may result from avariety of causes; (8) mis-registration of layers which may result frominaccuracies in applying masking material to previously formed layers inpreparation for forming subsequent layers; (9) sidewallroughness/non-vertical side walls which may result from lack ofcoherence in exposing masking material, improper development of maskingmaterial, and the like; (10) missing features in a 1^(St) depositedmaterial which may result from improper development of masking material,inability to deposit material into small openings in a masking material,and the like; (11) missing features in a 2^(nd) or subsequentlydeposited material which may result from inability to reliably removesmall pockets of masking material from a first deposited material or thelike; (12) poor quality deposition which may result form use ofimpropriate plating parameters or plating material baths, or the like;(13) cracks in a first deposited material which may result fromtemperature cycling or other causes, (14) cracks in a second orsubsequently deposited material which may result from temperaturecycling or other causes; (15) layer thickness error which may resultfrom insufficient, excess, or simply non-parallel planes ofplanarization of between a current layer and previous layers, (16)accumulated layer thickness error which may result, for example, frommeasuring height growth of a device layer-to-layer as opposed tomeasuring from a fixed reference level, and (17) errors found during orafter release of a structural material from a sacrificial material whichmay result from a failure to detect the error during layer-by-layerbuild up.

FIG. 9B sets forth numerous example remediation actions that may be usedin response to the build problems set forth in FIG. 9A as well as otherbuild problems that may be recognized. Some of these remedial actionsmay be better suited to solving some problems than others and in somesituations combining various remedial actions may be appropriate.

The first remedial action includes the thickening of the depositedmaterial on a layer, block 602. This action is particularly suited toaddressing inadequate layer thickness, block 504, and possibly layerthickness non-uniformity, block 526.

The second remedial action includes the removal of the current layer(e.g. planarize back to the boundary of the prior layer) and thenredeposit it, block 604. This action is particularly suited toaddressing voids and inclusions in deposited materials, block 508:porosity problems with depositions, block 512; deposition of the wrongmaterial or materials, block 514; distortion of geometric features inthe just deposited layer or partial layer, block 516; failure inadhesion between the just deposited layer or partial layer and apreviously deposited layer, block 522; failure in conductivity throughthe layer, block 524; a mechanical or electrical property being out ofspecification, blocks 528 and 530; when the just deposited layer orportion of a layer is found to be out of registration (i.e. X & Ypositioning of material on two consecutive layers does not provide theintended geometric relationship, block 534; missing features in a firstdeposition material on the layer or in a subsequently deposited materialon that layer, blocks 538 and 542; poor quality deposition of one ormore materials on a layer, block 544; and cracks in a first orsubsequently deposited material on a layer, blocks 546 and 548. Thisremediation technique is also applicable to some of the other problemslisted in FIG. 9A but other techniques may be more efficient inremedying the problems

The third remedial action includes the removal of the current layer plusδ of the prior layer then redeposition of the current layer such that itextends δ into the prior layer, block 606. This action is particularlysuited to addressing problems noted above in association with the secondremedial action particularly where the removed layer has regions ofstructural material that overlay regions of sacrificial material on theprevious layer so that it is ensured that all deposited material fromthe current layer is adequately removed or when a deposition of thewrongly deposited material has occurred.

The fourth remedial action includes the removal of a portion of thecurrent layer and then redeposition of that portion, block 608. Thisaction is particularly suited to addressing excess smearing problems,block 506; layer thickness non-uniformity problems, block 526; andpotentially when and cracks in a first or subsequently depositedmaterial on a layer occur, blocks 546 and 548. This remedial actionminimizes the time spent on rework while remove imperfections or flawsthat primarily exist on the exposure (e.g. upper surface) of the lastdeposited layer.

The fifth remedial action includes the removal of a portion of thecurrent layer and then deposition of the next layer such that it attainsa thickness equal to its intended thickness plus the overlap into thecurrent layer, block 612. This action is particularly suited toaddressing smearing problems, block 506; layer thickness non-uniformityproblems, block 526; and potentially when and cracks in a first orsubsequently deposited material on a layer occur, blocks 546 and 548.This remedial action allow problems to be corrected that exist only nearthe surface of a deposited layer where slight vertical inaccuracy inplacement of the next layer (e.g. the bottom portion of the law assumingthe layers are being stacked vertically) or in the thickness of the nextlayer is tolerable where time is saved by not having to remask andredeposit a thin incremental amount on a substantially formed layer.

The sixth remedial action includes the removal of multiple layers ofmaterial and the redeposition of them, block 616. This action isparticularly suited to addressing some of the same problems noted abovefor the second remedial action but more particularly when the error tobe corrected extends down into several layers, or when several layersmust be removed and reformed as a result of overall yield dropping belowa cutoff level which requires multi-layer reworking as opposed toscrapping the partial build and starting over.

The seventh remedial action includes the performance of a shallow ormicro-etch of a selected material, block 618 while the eighth remedialaction includes the performance of a shallow or micro-etch of allmaterials, block 622. These actions in combination with the secondremedial action are particularly suited to addressing adhesion failureproblems, block 522. These remedial actions may be converted intoanticipatory actions where it is believed that adhesion failure islikely. These remedial actions may also aid in establishing higheroptical contrast that may be useful in the process of visuallyinspecting layers or partially formed layers

The ninth remedial action includes the performance of a shallow etchback, after selective deposition and prior to a second deposition, block624. This action is particularly suited to addressing flash problems,block 502.

The tenth remedial action includes the removal of a portion of an entirelayer or the entire layer plus part of another layer based on ananalysis of critical layers or features and/or non-critical layers orfeatures and then redepositing the removed material such as to optimizecritical features or at least not to negatively impact criticalfeatures, block 632. This action is particularly suited to addressinglayer thickness error problems, block 552 and accumulated errorproblems, block 554, particularly when selected layer levels (levels onwhich critical features are to exist) need to be more precisely locatedthan normal layer leveling procedures allow.

The eleventh remedial action includes the release of a structure,examination of its features, then re-embedding the structure in asuitable material. This may be done so that planarization can occur withminimal concern for chipping or otherwise damaging edges of thestructural material at the planarization level, block 636.

The twelfth remedial action includes a physical label or creation of adata log of specific dies that are considered to have failed based onthe recognized problem, block 638. This action is particularly suited tothe batch formation of devices where problems have occurred on only asmall portion of the devices, and it is preferable to continue buildingand to take the yield loss as opposed to slowing the build process in anattempt to raise yield level. Of course if subsequent formationoperations result in failure of additional die (as opposed to the samedie) a point may be reached where yield loss is considered excessive,and removal of one or more layers of material may be necessitated tobring yield back to a desired level.

As with the first remedial action, the other remedial actions areparticularly suited to the problems noted above but they may also haveapplicability to greater or lesser extents to the other problems notedin FIG. 9A. Furthermore, in some embodiments, specific remedial actionsmay be combined with other remedial actions, or they may be implementedin a changing series starting with the most convenient remediationapproach followed by one or more less convenient, but possibly moreeffective, remediation techniques if the problem isn't alleviated in afirst or subsequent attempt.

Some embodiments may employ diffusion bonding or the like to enhanceadhesion between successive layers of material. Various teachingsconcerning the use of diffusion bonding in electrochemical fabricationprocess is set forth in U.S. Patent Application No. 60/534,204 which wasfiled Dec. 31, 2003 by Cohen et al. which is entitled “Method forFabricating Three-Dimensional Structures Including Surface Treatment ofa First Material in Preparation for Deposition of a Second Material” andwhich is hereby incorporated herein by reference as if set forth infull.

Teachings concerning the formation of structures on dielectricsubstrates and/or the formation of structures that incorporatedielectric materials into the formation process and possibility into thefinal structures as formed are set forth in a number of patentapplications filed on Dec. 31, 2003. The first of these filings is U.S.Patent Application No. 60/534,184, which is entitled “ElectrochemicalFabrication Methods Incorporating Dielectric Materials and/or UsingDielectric Substrates”. The second of these filings is U.S. PatentApplication No. 60/533,932, which is entitled “ElectrochemicalFabrication Methods Using Dielectric Substrates”. The third of thesefilings is U.S. Patent Application No. 60/534,157, which is entitled“Electrochemical Fabrication Methods Incorporating DielectricMaterials”. The fourth of these filings is U.S. patent Application No.60/533,891, which is entitled “Methods for Electrochemically FabricatingStructures Incorporating Dielectric Sheets and/or Seed layers That ArePartially Removed Via Planarization”. A fifth such filing is U.S. PatentApplication No. 60/533,895, which is entitled “ElectrochemicalFabrication Method for Producing Multi-layer Three-DimensionalStructures on a Porous Dielectric”. These patent filings are each herebyincorporated herein by reference as if set forth in full herein.

The patent applications and patents set forth below are herebyincorporated by reference herein as if set forth in full. The teachingsin these incorporated applications can be combined with the teachings ofthe instant application in many ways: For example, enhanced methods ofproducing structures may be derived from some combinations of teachings,enhanced structures may be obtainable, enhanced apparatus may bederived, and the like.

US Pat App No., Filing Date US App Pub No., Pub Date U.S. Pat. No., PubDate Inventor, Title 09/493,496 - Jan. 28, 2000 Cohen, “Method ForElectrochemical Fabrication” PAT 6,790,377 - Sep. 14, 2004 10/677,556 -Oct. 1, 2003 Cohen, “Monolithic Structures Including Alignment and/or2004 -0134772 - Jul. 15, 2004 Retention Fixtures for AcceptingComponents” 10/830,262 - Apr. 21, 2004 Cohen, “Methods of ReducingInterlayer Discontinuities in 2004-0251142A - Dec. 16, 2004Electrochemically Fabricated Three-Dimensional Structures” PAT7,198,704 - Apr. 3, 2007 10/271,574 -Oct. 15, 2002 Cohen, “Methods ofand Apparatus for Making High Aspect 2003-0127336A - July 10, 2003 RatioMicroelectromechanical Structures” PAT 7,288,178 - Oct. 30, 200710/697,597 - Dec. 20, 2002 Lockard, “EFAB Methods and ApparatusIncluding Spray 2004-0146650A - Jul. 29, 2004 Metal or Powder CoatingProcesses” 10/677,498 - Oct. 1, 2003 Cohen, “Multi-cell Masks andMethods and Apparatus for 2004-0134788 - Jul. 15, 2004 Using Such MasksTo Form Three-Dimensional Structures” PAT 7,235,166 - Jun. 26, 200710/724,513 - Nov. 26, 2003 Cohen, “Non-Conformable Masks and Methods and2004-0147124 - Jul. 29, 2004 Apparatus for Forming Three-DimensionalStructures” PAT 7,368,044 - May 6, 2008 10/607,931 - Jun. 27, 2003Brown, “Miniature RF and Microwave Components and 2004-0140862 - Jul.22, 2004 Methods for Fabricating Such Components” PAT 7,239,219 - Jul.3, 2007 10/841,100 - May 7, 2004 Cohen, “Electrochemical FabricationMethods Including Use 2005-0032362 - Feb. 10, 2005 of Surface Treatmentsto Reduce Overplating and/or PAT 7,109,118 - Sep. 19, 2006 PlanarizationDuring Formation of Multi-layer Three- Dimensional Structures”10/387,958 - Mar. 13, 2003 Cohen, “Electrochemical Fabrication Methodand 2003-022168A - Dec. 4, 2003 Application for ProducingThree-Dimensional Structures Having Improved Surface Finish”10/434,494 - May 7, 2003 Zhang, “Methods and Apparatus for MonitoringDeposition 2004-0000489A - Jan. 1, 2004 Quality During ConformableContact Mask Plating Operations” 10/434,289 - May 7, 2003 Zhang,“Conformable Contact Masking Methods and 20040065555A - Apr. 8, 2004Apparatus Utilizing In Situ Cathodic Activation of a Substrate”10/434,294 - May 7, 2003 Zhang, “Electrochemical Fabrication MethodsWith 2004-0065550A - Apr. 8, 2004 Enhanced Post Deposition Processing”10/434,295 - May 7, 2003 Cohen, “Method of and Apparatus for FormingThree- 2004-0004001A - Jan. 8, 2004 Dimensional Structures Integral WithSemiconductor Based Circuitry” 10/434,315 - May 7, 2003 Bang, “Methodsof and Apparatus for Molding Structures 2003-0234179 A - Dec. 25, 2003Using Sacrificial Metal Patterns” PAT 7,229,542 - Jun. 12, 200710/434,103 - May 7, 2004 Cohen, “Electrochemically FabricatedHermetically Sealed 2004-0020782A - Feb. 5, 2004 Microstructures andMethods of and Apparatus for PAT 7,160,429 - Jan. 9, 2007 Producing SuchStructures” 10/841,006 - May 7, 2004 Thompson, “ElectrochemicallyFabricated Structures Having 2005-0067292 - May 31, 2005 Dielectric orActive Bases and Methods of and Apparatus for Producing Such Structures”10/434,519 - May 7, 2003 Smalley, “Methods of and Apparatus forElectrochemically 2004-0007470A - Jan. 15, 2004 Fabricating StructuresVia Interlaced Layers or Via Selective PAT 7,252,861 - Aug. 7, 2007Etching and Filling of Voids” 10/724,515 - Nov. 26, 2003 Cohen, “Methodfor Electrochemically Forming Structures 2004-0182716 - Sep. 23, 2004Including Non-Parallel Mating of Contact Masks and PAT 7,291,254 - Nov.6, 2007 Substrates” 10/841,347 - May 7, 2004 Cohen, “Multi-step ReleaseMethod for Electrochemically 2005-0072681 - Apr. 7, 2005 FabricatedStructures” 60/533,947 - Dec. 31, 2003 Kumar, “Probe Arrays and Methodfor Making” 60/534,183 - Dec. 31, 2003 Cohen, “Method and Apparatus forMaintaining Parallelism of Layers and/or Achieving Desired Thicknessesof Layers During the Electrochemical Fabrication of Structures”11/733,195 - Apr. 9, 2007 Kumar, “Methods of Forming Three-DimensionalStructures 2008-0050524 - Feb. 28, 2008 Having Reduced Stress and/orCurvature” 11/506,586 - Aug. 8, 2006 Cohen, “Mesoscale and MicroscaleDevice Fabrication 2007-0039828 - Feb. 22, 2007 Methods Using SplitStructures and Alignment Elements” PAT 7,611,616 - Nov. 3, 200910/949,744 - Sep. 24, 2004 Lockard, “Three-Dimensional Structures HavingFeature 2005-0126916 - Jun. 16, 2005 Sizes Smaller Than a MinimumFeature Size and Methods PAT 7,498,714 - Mar. 3, 2009 for Fabricating”

Various other embodiments of the present invention exist. Some of theseembodiments may be based on a combination of the teachings herein withvarious teachings incorporated herein by reference. Some embodiments maynot use any blanket deposition process and/or they may not use aplanarization process. Some embodiments may involve the selectivedeposition of a plurality of different materials on a single layer or ondifferent layers. Some embodiments may use blanket or selectivedepositions processes that are not electrodeposition processes. Someembodiments may use conformable contact masks, non-conformable masks,proximity masks, and/or adhered masks for selective patterningoperations. Some embodiments may use nickel as a structural materialwhile other embodiments may use different materials such as gold,silver, or any other electrodepositable materials that can be separatedfrom the selected sacrificial material (e.g. copper and/or some othersacrificial material). Some embodiments may use copper as the structuralmaterial with or without a sacrificial material. Some embodiments mayremove a sacrificial material while other embodiments may not. In someembodiments, the depth of deposition may be enhanced by pulling theconformable contact mask away from the substrate as deposition isoccurring in a manner that allows the seal between the conformableportion of the CC mask and the substrate to shift from the face of theconformal material to the inside edges of the conformable material.

In some embodiments, monitoring of build problems may occur viaautomated detection systems. For example, voltage monitoring or currentmonitoring during plating; resistance testing, performance of variousmechanical tests, such as impact testing; automatic or manual visualinspection with or without comparison targets, and the like. Other testswill be apparent to those of skill in the art.

In view of the teachings herein, many further embodiments, alternativesin design and uses of the instant invention will be apparent to those ofskill in the art. As such, it is not intended that the invention belimited to the particular illustrative embodiments, alternatives, anduses described above but instead that it be solely limited by the claimspresented hereafter.

1. An electrochemical fabrication process for batch producing of aplurality of three-dimensional structures from a plurality of adheredlayers, the process comprising: (A) selectively depositing a firstmaterial of a first layer onto the substrate, wherein the substrate maycomprise previously deposited material, depositing a second material ofthe first layer onto the substrate, and planarizing the first and secondmaterials of the first layer to set a boundary level of the first layer;(B) forming a plurality of layers such that successive layers are formedadjacent to and adhered to previously formed layers, wherein saidforming of the plurality of layers comprises repeating the operations ofstep (A) a plurality of times; wherein a selective depositing stepassociated with the forming of a given layer of the plurality of layers,comprises: (1) providing a mask having at least one opening to thesubstrate or to an immediately preceding layer; (2) in presence of aplating solution, conducting an electric current between an anode andthe substrate or the immediately preceding layer through the at leastone opening in the mask, such that a first material for the given layeris deposited onto the substrate or onto the immediately preceding layerto form a portion of the given layer; and (3) removing the mask from thesubstrate or previously formed layer; (C) after the forming of theplurality of layers, removing at least one of the deposited materialsfrom a plurality of layers to reveal the three-dimensional structures,wherein during the forming of the plurality of layers, (i) identifyingstructures that are considered to have failed, (ii) maintaining a datalog of failed structures, (iii) periodically determining if the numberof failed structures is excessive, and (iv) if the number of failedstructures is considered excessive, removing one or more layers; and(vi) repeating the forming of the one or more layers that had beenremoved.
 2. The process of claim 1, wherein the first material depositedto form each of a plurality of layers and the second material depositedto form each of the plurality of layers comprises at least onestructural material and at least one sacrificial material.
 3. Theprocess of claim 1 wherein the identification is, at least in part basedon a visual inspection.
 4. An electrochemical fabrication process forbatch producing of a plurality of three-dimensional structures from aplurality of adhered layers, the process comprising: (A) selectivelydepositing a first material of a first layer onto the substrate, whereinthe substrate may comprise previously deposited material, depositing asecond material of the first layer onto the substrate, and planarizingthe first and second materials of the first layer to set a boundarylevel of the first layer; (B) forming a plurality of layers such thatsuccessive layers are formed adjacent to and adhered to previouslyformed layers, wherein said forming of the plurality of layers comprisesrepeating the operations of step (A) a plurality of times; wherein aselective depositing step associated with the forming of a given layerof the plurality of layers, comprises: (1) providing a mask having atleast one opening to the substrate or to an immediately preceding layer;(2) in presence of a plating solution, conducting an electric currentbetween an anode and the substrate or the immediately preceding layerthrough the at least one opening in the mask, such that a first materialfor the given layer is deposited onto the substrate or onto theimmediately preceding layer to form a portion of the given layer; and(3) removing the mask from the substrate; (C) releasing at least aportion of the structures from one of the deposited materials, which isa sacrificial material; (D) re-embedding the structures in a sacrificialmaterial; (E) removing at least a portion of the re-embedded structuresby planarization; and (F) removing the three-dimensional structures fromthe re-embedding sacrificial material to release the three-dimensionalstructures.
 5. The process of claim 4, wherein the first materialdeposited to form each of a plurality of layers and the second materialdeposited to form each of the plurality of layers comprises at least onestructural material and at least one sacrificial material.
 6. Theprocess of claim 4 wherein the plurality of selective depositionscomprise the deposition of a plurality of different materials.
 7. Theprocess of claim 4 wherein at least a portion of one layer is formed bya non-electroplating deposition process.